No one should begrudge a band that wants to re-form. Why condemn musicians for wanting to earn money from songs they wrote, by playing them to people who want to hear them? Nevertheless, there is dignity in the restraint displayed by Led Zeppelin when they quashed fans' hopes that a much trailed announcement might be a reunion tour – it turned out to be a DVD of their only full show since their split, the tribute to their mentor Ahmet Ertegun in 2007. That show was the model of a perfect reunion: it was not to swell already swollen coffers; it enabled the band's surviving members to restate their musical legacy without it having to overshadow the rest of their lives all over again; and the fact it was just a single show meant their status as one of rock's one-offs was not sullied by familiarity. Led Zeppelin knew in the 1970s that reticence could be a virtue – hence their no-singles, no-TV rule. Evidently, they still do.